Rocky: Replicating Block Devices for Tamper and Failure Resistant Edge-based Virtualized Desktop Infrastructure

Recently, edge-based virtual desktop infrastructure (EdgeVDI), which brings the power of virtualized desktop infrastructure to cloudlets closer to users, has been considered as an attractive solution for WAN mobility. However, ransomware and wiper malware are becoming more and more prevalent, which can impose serious cybersecurity threats to EdgeVDI users. Existing tamper-resistant solutions cannot deal with cloudlet failures. In this paper, we propose Rocky, the first distributed replicated block device for EdgeVDI that can recover from tampering attacks and failures. The key enabler is replicating to store a consistent write sequence across cloudlets as an append-only immutable mutation history. In addition, Rocky uses a replication broker to allow heterogenous cloudlets to control replication rates at their pace and reduces both disk space and network bandwidth consumption by coalescing writes for both uplink and downlink. To show the feasibility of Rocky, we implemented Rocky in Java. The experimental results show that Rocky's write and read throughputs are similar to those of a baseline device with 8.4% and 11.9% additional overheads, respectively. In addition, we could reduce repeated writes by 88.5% and 100% for editing presentation slides and a photo, respectively.